SHANMUGAM IAS ACADEMY

Thursday, February 28, 2013

The International Monetary Fund (IMF) is an organization of 188 countries, working to foster global monetary cooperation, secure financial stability, facilitate international trade, promote high employment and sustainable economic growth, and reduce poverty around the world.The Bretton Woods agreementTheIMF was conceivedin July 1944, when representatives of 45 countries meeting in the town of Bretton Woods, New Hampshire, in the northeastern United States, agreed on a framework for international economic cooperation, to be established after the Second World War. They believed that such a framework was necessary to avoid a repetition of the disastrous economic policies that had contributed to the Great Depression.The IMF came into formal existence in December 1945, when its first 29 member countries signed itsArticles of Agreement. It began operations on March 1, 1947. Later that year, France became the first country to borrow from the IMF.The IMF's membership began to expand in the late 1950s and during the 1960s as many African countries became independent and applied for membership. But the Cold War limited the Fund's membership, with most countries in the Soviet sphere of influence not joining.

1945 February: Yalta Conference of the ‘Big Three’ (Roosevelt, Churchill and Stalin) decides to organise a United Nations conference on the proposed world organisation April-May: The 2-month long United Nations Conference on International Organisation at San Francisco

1945 June 26: Signing of the UN Charter by 50 nations (Poland signed on October 15; so the UN has 51 original founding members)

1945 October 24: the UN was founded (hence October 24 is celebrated as UN Day)

Individually, Chidambaram presented the Union Budget for the eighth time, the second-highest by any Finance Minister.

The maximum number of 10 Budgets have been presented by Morarji Desai, while Pranab Mukherjee (currently President of the country), Yashwant Sinha, Y B Chavan and C D Deshmukh have presented seven Budgets each in the past.

Prime Minister Manmohan Singh and the country's fourth Finance Minister T T Krishnamachari have presented six Budgets each during their tenures in the Finance Ministry.

Among others, R Venkatraman and H M Patel have presented three Budgets each, while Jaswant Singh, V P Singh, C Subramaniam, John Mathai and R K Shanmukham Chetty have two Budgets each to their credits.

So far, the country has seen 66 normal annual Budgets, while there have been 12 interim Budgets and four special-occasion Budgetary proposals, also known as mini Budgets.

The first such mini-Budget was presented by T T Krishnamachari on November 30, 1956 in form of fresh taxation proposals through Finance Bills, demanded by the prevailing domestic and international economic situation.

The step was also required to tackle issues like rising inflation and dwindling forex reserves at that time.

The second mid-year Budget taxation proposals were also presented by Krishnamachari in August 1965, while the third mini-Budget was presented by Y B Chavan in December 1971 wherein he proposed additional measures for mobilisation of resources for defence requirements.

The last mini-Budget proposals in Parliament was also made by Chavan in July 1974, wherein he made fresh taxation proposals to tackle inflation-related issues after only five months of the regular annual Budget.

The proposed bank will lend mostly to women and women run
businesses, support women SHGs and womens livelihood, It will employ predominately women which
addresses the gender related issues and empowerment and financial inclusion.

Monday, February 25, 2013

Commercialisation: The process of transforming something into a product, service or activity that has economic value and can be traded in the market

Culture: Culture was understood as that which referred to knowledge, belief, art, morals, law, custom and any other capabilities and habits acquired by man as a member of society.

Decentralisation: Refers to a process of gradual devolution or transfer of functions, resources and decision- making powers to the lower-level democratically elected bodies.

Digitalisation: Refers to the process whereby information is produced as a universal binary code, and can thus be easily processed, stored and circulated at greater speed across communication technologies like internet, satellite transmission, telephones, fiber optic lines etc.

Disinvestment: Privatisation of public sector or government companiesDivision of labour: Specialisation of tasks in ways that may involve exclusion from some opportunities. Hence, closure of labour opportunities exist in employment or by gender.

Diversification: Spread of investment into different types of economic activities in order to reduce risks.

Fordism: Refers to a system of production made popular by the American industrialist Henry Ford in the early part of 20th century. He popularized the assembly line method of mass production of a standardized product (cars). This era also led to payment of better wages to the workers and social welfare policies being implemented by both industrialists and the state.

Great and Little Tradition: The ways of folks or unlettered peasants constitute the Little Traditions and that of the elite or the reflective few the Great Tradition. While the Little Tradition is often localised, Great Tradition has a tendency to spread out. However studies of festivals in India will show how sanskritic rites (Great Tradition) are often added to non Sanskritic rites (Little Tradition) without replacing them.

Identity politics: Refers to a range of political activities that are founded in the shared experiences of a particular marginalized group such as gender, race, ethnic group etc.

Import-substitution development strategy: The import substitution substitutes externally produced goods and services, especially basic necessities such as food, water, energy. The notion of import substitution was popularized in the 1950s and 1960s to promote economic independence of development in developing countries.

Industrialization: The development of modern forms of industry- factories, machines and large-scale production processes. Industrialization has beenone of the main sets of processes influencing the social world over the past two centuries.

Means of production: The means whereby the production of material goods is carried on in a society, including not just technology but the social relations between producers

Micro-electronics: The branch of electronics dealing with the miniaturization of components and circuits. The giant step in the field of micro-electronics came in 1971 with the invention by an Intel engineer of the microprocessor that is a computer on a chip. In 1971, 2,300 transistors (a device for controlling flow of electricity) were packed on a chip of the size of a thumbtack, in 1993, there were 35 million transistors. Compare this with the first electronic computer which weighed 30 tons, was built on metal stands 9 feet tall and occupied the area of a gymnasium.

Mono crop regime: Planting a single crop or type of seed over a large area.

Norms: The normative dimension consists of folkways, mores, customs, conventions and laws. These are values or rules that guide social behaviour in different contexts. We most often follow social norms because we are used to doing it, as a result of socialisation. All social norms are accompanied by sanctions that promote conformity. While norms are implicit rules, laws are explicit rules.

Optic fiber: A thin glass strand designed for light transmission. A single hair-thin fiber is capable of transmitting trillions of bits of information per second while a thin copper wire which was used earlier could transmit only 144,000 bits of information.

Outsourcing: Giving work out to other companies.

Patrilineality: A system in which one belongs to one’s father’s lineage or family;

Piece rate wage: Payment on the basis of items produced.

Post-Fordism: Refers to the method of flexible production adopted by multinational companies who either off-shore their production units or outsource the whole process of production and distribution to third world countries because of the availability of cheap labour. This period also marks the growth of the financial sector and growth of the culture and leisure industry evident in the appearance in cities of shopping malls, multiplex cinema halls, amusement parks and the phenomenal growth in television
channels.

Raiyatwari system: A system of tax collection in colonial India in which the government settled the revenue directly with the cultivator.

Reference Group: The social group which an individual or group desires to be like and therefore adopts their ways of dressing and behaving. Usually the reference group occupies a dominant position in society.

Sensex or Nifty index: These are indicators of the rise or fall in the share of the major companies. Sensex is the indicator of the shares of the major companies at the Bombay Stock Exchange (BSE) while Nifty is the indicator for the companies at the National Stock Exchange (NSE) located in New Delhi.

Social Fact: According to Emile Durkheim they refer to those aspects of social life that shape our actions as individuals.

Sovereignty: The title to supreme power of a monarch, leader or government over an area with a clear-cut border.

Structure: Was widely seen as web of interactions, which are both regular and recurrent

Taylorism: System invented by Taylor, involving break up of work under management control.

Values: Ideas held by human individuals or groups about what is desirable, proper, good or bad. Differing values represent key aspects of variations in human culture. What individuals value is strongly influenced by the specific culture in which they happen to live.Urbanisation: The development of towns and citiesZamindari system: A system of tax collection in colonial India in which the zamindar would collect all taxes on his lands and hen hand the revenue over to the British a authorities (keeping a portion for himself)

Sunday, February 24, 2013

Indian Parliament comprises President of India and two houses, Lok Sabha (House of the People) and Rajya Sabha (Council of States).
There are 790 Members of Parliament (MPs), representing the largest democratic electorate in the world (714 million eligible voters in 2009).
Parliament is housed in Sansad Bhavan, the foundation stone of which was laid on February 12, 1921. It was completed in six years at a cost of ` 8.3 million. Circular in design, it has 144 pillars and 560 feet diameter and covers nearly six acres.
Parliament’s first sitting was on May 13, 1952. The Indian Parliament holds three sessions in a year: The Budget Session (February-May); Monsoon Session (July-August); and the Winter Session (November-December).
The first Lok Sabha had 22 women among its 499 members. The 15th Lok Sabha has a record 59.
The percentage of graduate MPs has increased from 58 per cent in 1952 to 79 per cent in 2009.
At present, more MPs have post-graduate degrees than in 1952, an increase from 18 per cent to 29 per cent.
At 29, Hamidullah Sayeed is the youngest member of the 15th Lok Sabha. There are 30 MPs below the age of 35 in this Parliament; another 30 MPs are between the age of 36 and 39. Six under-35 MPs are women.

Rishang Keishing (92) is the oldest parliamentarian who got elected to the first 1952-57 Lok Sabha.
India became a Republic on November 26, 1949. But the first general elections were held in 1951-52.
Constituted on April 17, 1952, the Lok Sabha held its first session a month later, starting May 13.
One of the first things Parliament acted on was how to give land to the landless through Land reforms act.
Bhagwati Devi, a stone quarry worker from Gaya, and Phoolan Devi, a former dacoit from Chambal, were among the elected members of the house.
Both the Lok Sabha and the Rajya Sabha met at quarter to eleven in the morning on the first day of the first session of the first Parliament of India.
President Pratibha Patil released coins of ` 5 and ` 10 denomination to mark 60 years of Parliament along with a special stamp.

Rabindranath Tagore: A Commemorative Volume and Rabindranath Tagore: An Interpretation have
been released to mark Tagore’s 150th birth anniversary. The first Asian Noble Laureate and the only
Indian Noble Laureate for Literature, he composed the national anthems for both India and Bangladesh. He wrote poetry, novels, essays, plays and short stories and was a painter. In Bengali, his collected writings fill 31 volumes . Comparisons are often drawn between him and Irish nationalist and cultural revivalist W.B. Yeats, who introduced Tagore’s works in English to the West. Both resonate of the Romantics. Tagore’s mystical symbolism is compared with English poet-painter William Blake. Some
of his paintings compare with Blake’s, although he was more than just a mystic.
It was Tagore who named Gandhi ‘Mahatma’. That is not to say that the two agreed on everything. Whilst Tagore placed emphasis on the village and traditional Indian civilisation, he also placed faith in science and the scientific method, talking with Einstein and Heisenberg. His knowledge of villages came from his time as a manager for his family estates in what is now Bangladesh.
A school he established in Santiniketan exists to this day (Prime Minister Indira Gandhi was a student). He pioneered co-educational teaching and was more progressive on gender issues than others at that time and place. An avid traveller, Tagore visited Japan, South America, Europe, the former USSR, China and the Middle East. He also visited Italy at Mussolini’s invitation, but later denounced the dictator. He intervened in public debates against the British Raj on a range of issues. In 1919, he renounced his knighthood in protest against the Jalianwalla Bagh Massacre.
Tagore was attracted to the concept of unity in diversity. He was 80 years old when he died in Kolkata (then Calcutta) on August 7, 1941.

The Valley of Flowers is a marvel of nature. Once the snow melts in the valley, from May onwards, various plant species start flowering. This flowering continues till September. The Valley covers an area of 87.5 sq km over an altitude varying from 3,200 to 6,600 m with its main area of about 10 sq km running in the east-west direction along the river Pushpawati. The trek to the Valley starts from Govindghat. The 13-km trek to Ghangaria moves along the river Bhyndar. The trek till Bhyndar, 10 km away, is rather comfortable. From Bhyndar it is a steep climb to Ghangaria. The landscape near the Bhyndar village is painted with mountains, waterfalls and forests. Pink and white roses greet us on this stretch.

Sighting the tiger in the Sunderbans is a thrilling experience. The excitement builds up in Kolkata from where the journey begins. The Sunderbans, situated along the southern tip of West Bengal, is 4,262 sq km of watery wilderness, of which 2,585 sq km are part of the tiger reserve. The area is a UNESCO world heritage site, being a unique example of an estuarine mangrove ecosystem.
The Royal Bengal Tiger is lord of the jungle. The 2011 tiger census puts the number of tigers in the region at 270. It is the only tiger that lives in a mangrove forest. There are several watch towers inside the forest which offer a panoramic view of the surrounding forest. Waterholes have been dug in the areas to attract wild animals. It is possible to see spotted deer, monkeys, fishing cats, wild boars and crocodiles. There is also a turtle hatchery that takes care of the endangered Olive Ridley turtles.
One particularly interesting fish that is found here is the mudskipper, a gobioid that climbs out of the water into mudflats and even climbs trees. The mudflats and creeks harbour a lot of birds, among them are such rarities as the Masked Finfoot, Mangrove Pitta and the Mangrove Whistler.

Saturday, February 23, 2013

Arrhenius was born near Uppsala, Sweden. He presented his thesis, on the conductivities of electrolyte solutions, to the University of Uppsala in 1884. For the next five years he travelled extensively and visited a number of research centers in Europe. In 1895 he was appointed professor of physics at the newly formed University of Stockholm, serving its rector from 1897 to 1902. From 1905 until his death he was Director of physical chemistry at the Nobel Institute in Stockholm. He continued to work for many years on electrolytic solutions. In 1899 he discussed the temperature dependence of reaction rates on the basis of an equation, now usually known as Arrhenius equation. He worked in a variety of fields, and made important contributions to immunochemistry, cosmology, the origin of life, and the causes of ice age. He was the first to discuss the ‘green house effect’ calling by that name. He received Nobel Prize in Chemistry in 1903 for his theory of electrolytic dissociation and its use in the development of chemistry.

Faraday was born near London into a family of very limited means. At the age of 14 he was an apprentice to a kind bookbinder who allowed Faraday to read the books he was binding. Through a fortunate chance he became laboratory assistant to Davy, and during 1813-4, Faraday accompanied him to the Continent. During this trip he gained much from the experience of coming into contact with many of the leading scientists of the time. In 1825, he succeeded Davy as Director of the Royal Institution laboratories, and in 1833 he also became the first Fullerian Professor of Chemistry. Faraday’s first important work was on analytical chemistry. After 1821 much of his work was on electricity and magnetism and different electromagnetic phenomena. His ideas have led to the establishment of modern field theory. He discovered his two laws of electrolysis in 1834. Faraday was a very modest and kind hearted person. He declined all honours and avoided scientific controversies. He preferred to work alone and never had any assistant. He disseminated science in a variety of ways including his Friday evening discourses, which he founded at the Royal Institution. He has been very famous for his Christmas lecture on the ‘Chemical History of a Candle’. He published nearly 450 scientific papers.

Dmitri Mendeleev was born in Tobalsk, Siberia in Russia. After his father’s death, the family moved to St. Petersburg. He received his Master’s degree in Chemistry in 1856 and the doctoral degree in 1865. He taught at the University of St.Petersburg where he was appointed Professor of General Chemistry in 1867. Preliminary work for his great textbook “Principles of Chemistry” led Mendeleev to propose the Periodic Law and to construct his Periodic Table of elements. At that time, the structure of atom was unknown and Mendeleev’s idea to consider that the properties of the elements were in someway related to their atomic masses was a very imaginative one. To place certain elements into the correct group from the point of view of their chemical properties, Mendeleev reversed the order of some pairs of elements and asserted that their atomic masses were incorrect. Mendeleev also had the foresight to leave gaps in the Periodic Table for elements unknown at that time and predict their properties from the trends that he observed among the properties of related elements. Mendeleev’s predictions were proved to be astonishingly correct when these elements were discovered later.

Mendeleev’s Periodic Law spurred several areas of research during the subsequent decades. The discovery of the first two noble gases helium and argon in 1890 suggested the possibility that there must be other similar elements to fill an entire family. This idea led Ramsay to his successful search for krypton and xenon. Work on the radioactive decay series for uranium and thorium in the early years of twentieth century was also guided by the Periodic Table.

Mendeleev was a versatile genius. He worked on many problems connected with Russia’s natural resources. He invented an accurate barometer. In 1890, he resigned from the Professorship. He was appointed as the Director of the Bureau of Weights and Measures. He continued to carry out important research work in many areas until his death in 1907.

Mendeleev’s name has been immortalized by naming the element with atomic number 101, as Mendelevium. This name was proposed by American scientist Glenn T. Seaborg, the discoverer of this element, “in recognition of the pioneering role of the great Russian Chemist who was the first to use the periodic system of elements to predict the chemical properties of undiscovered elements, a principle which has been the key to the discovery of nearly all the transuranium elements”.

Erwin Schrödinger, an Austrian physicist received his Ph.D. in theoretical physics from the University of Vienna in 1910. In 1927 Schrödinger succeeded Max Planck at the University of Berlin at Planck’s request. In 1933, Schrödinger left Berlin because of his opposition to Hitler and Nazi policies and returned to Austria in 1936. After the invasion of Austria by Germany, Schrödinger was forcibly removed from his professorship. He then moved to Dublin, Ireland where he remained for seventeen years. Schrödinger shared the Nobel Prize for Physics with P.A.M. Dirac in 1933.

Werner Heisenberg (1901 – 1976) received his Ph.D. in physics from the University of Munich in 1923. He then spent a year working with Max Born at Gottingen and three years with Niels Bohr in Copenhagen. He was professor of physics at the University of Leipzig from 1927 to 1941. During World War II, Heisenberg was in charge of German research on the atomic bomb. After the war he was named director of Max Planck Institute for physics in Gottingen. He was also accomplished mountain climber. Heisenberg was awarded the Nobel Prize in Physics in 1932.

Max Planck, a German physicist, received his Ph.D in theoretical physics from the University of Munich in 1879. In 1888, he was appointed Director of the Institute of Theoretical Physics at the University of Berlin. Planck was awarded the Nobel Prize in Physics in 1918 for his quantum theory. Planck also made significant contributions in thermodynamics and other areas of physics.

Metre (m): The metre is the length of path travelled by light in vacuum during a time interval of 1/299 792 458 of a second.

Kilogram (kg): The kilogram is the unit of mass; it is equal to the mass of the international prototype of the kilogram.

Second (s): The second is the duration of 9192631770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom.

Ampere (A): The ampere is that constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section, and placed 1 metre apart in vacuum, would produce between these conductors a force equal to 2 10 -7 Newton per metre of length.

Kelvin (K): The kelvin, unit of thermodynamic temperature, is the fraction 1/273.16 of the thermodynamic temperature of the triple point of water.

Mole (mol): The mole is the amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kilogram of carbon-12. When the mole is used, the elementary entities must be specified and may be atoms, molecules, ions, electrons, other particles, or specified groups of such particles.

Candela (cd): The candela is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540 1012 hertz and that has a radiant intensity in that direction of (1/683) watt per steradian.

It is known that every individual has unique fingerprints. These occur at the tips of the fingers and have been used for identification for a long time but these can be altered by surgery. A sequence of bases on DNA is also unique for a person and information regarding this is called DNA fingerprinting. It is same for every cell and cannot be altered by any known treatment. DNA fingerprinting is now used

(i) in forensic laboratories for identification of criminals.

(ii) to determine paternity of an individual.

(iii) to identify the dead bodies in any accident by comparing the DNA’s of parents or children.

Har Gobind Khorana, was born in 1922. He obtained his M.Sc. degree from Punjab University in Lahore. He worked with Professor Vladimir Prelog, who moulded Khorana’s thought and philosophy towards science, work and effort. After a brief stay in India in 1949, Khorana went back to England and worked with Professor G.W. Kenner and Professor A.R.Todd. It was at Cambridge, U.K. that he got interested in both proteins and nucleic acids. Dr Khorana shared the Nobel Prize for Medicine and Physiology in 1968 with Marshall Nirenberg and Robert Holley for cracking the genetic code.

Victor Grignard had a strange start in academic life for a chemist - he took a maths degree. When he eventually switched to chemistry, it was not to the mathematical province of physical chemistry but to organic chemistry. While attempting to find an efficient catalyst for the process of methylation, he noted that Zn in diethyl ether had been used for this purpose and wondered whether the Mg/ether combination might be successful. Grignard reagents were first reported in 1900 and Grignard used this work for his doctoral thesis in 1901. In 1910, Grignard obtained a professorship at the University of Nancy and in 1912, he was awarded the Nobel prize for Chemistry which he shared with Paul Sabatier who had made advances in nickel catalysed hydrogenation.

Werner was born on December 12, 1866, in Mülhouse, a small community in the French province of Alsace. His study of chemistry began in Karlsruhe (Germany) and continued in Zurich (Switzerland), where in his doctoral thesis in 1890, he explained the difference in properties of certain nitrogen containing organic substances on the basis of isomerism. He extended vant Hoff’s theory of tetrahedral carbon atom and modified it for nitrogen. Werner showed optical and electrical differences between complex compounds based on physical measurements. In fact, Werner was the first to discover optical activity in certain coordination compounds.
He, at the age of 29 years became a full professor at Technische Hochschule in Zurich in 1895. Alfred Werner was a chemist and educationist. His accomplishments included the development of the theory of coordination compounds. This theory, in which Werner proposed revolutionary ideas about how atoms and molecules are linked together, was formulated in a span of only three years, from 1890 to 1893. The remainder of his career was spent gathering the experimental support required to validate his new ideas. Werner became the first Swiss chemist to win the Nobel Prize in 1913 for his work on the linkage of atoms and the coordination theory.

At present the main source of energy that is driving our economy
is fossil fuels such as coal, oil and gas. As more people on the planet aspire
to improve their standard of living, their energy requirement will increase. In
fact, the per capita consumption of energy used is a measure of development. Of
course, it is assumed that energy is used for productive purpose and not merely
wasted. We are already aware that carbon dioxide produced by the combustion of
fossil fuels is resulting in the ‘Greenhouse Effect’. This is leading to a rise
in the temperature of the Earth’s surface, causing polar ice to melt and ocean
levels to rise. This will flood low-lying areas along the coast and some island
nations such as Maldives face total submergence. In order to avoid such a
catastrope, we need to limit our use of carbonaceous fuels. Hydrogen provides
an ideal alternative as its combustion results in water only. Hydrogen
production must come from splitting water using solar energy. Therefore,
hydrogen can be used as a renewable and non polluting source of energy. This is
the vision of the Hydrogen Economy. Both the production of hydrogen by
electrolysis of water and hydrogen combustion in a fuel cell will be important in
the future. And both these technologies are based on electrochemical
principles.

An electrochemical cell
consists of two metallic electrodes dipping in electrolytic solution(s). Thus
an important component of the electrochemical cell is the ionic conductor or
electrolyte. Electrochemical cells are of two types. In galvanic cell, the
chemical energy of a spontaneous redox reaction is converted into electrical
work, whereas in an electrolytic cell, electrical energy is used to carry out a
non-spontaneous redox reaction. The standard electrode potential for any
electrode dipping in an appropriate solution is defined with respect to
standard electrode potential of hydrogen electrode taken as zero. The standard
potential of the cell can be obtained by taking the difference of the standard
potentials of cathode and anode. The standard potential of the cells are
related to standard Gibbs energy and equilibrium constant of the reaction
taking place in the cell. Concentration dependence of the potentials of the electrodes
and the cells are given by Nernst equation.

The conductivity, κ, of an electrolytic solution
depends on the concentration of the electrolyte, nature of solvent and
temperature. Molar conductivity, Ëm, is defined by = κ /c where c is the
concentration. Conductivity decreases but molar conductivity increases with
decrease in concentration. It increases slowly with decrease in concentration
for strong electrolytes while the increase is very steep for weak electrolytes
in very dilute solutions. Kohlrausch found that molar conductivity at infinite
dilution, for an electrolyte is sum of the contribution of the molar
conductivity of the ions in which it dissociates. It is known as law of
independent migration of ions and has many applications. Ions conduct
electricity through the solution but oxidation and reduction of the ions take
place at the electrodes in an electrochemical cell. Batteries and fuel cells
are very useful forms of galvanic cell. Corrosion of metals is essentially an
electrochemical phenomenon. Electrochemical principles are relevant to the Hydrogen
Economy.

Solids have definite mass, volume and shape. This is due to the fixed position of their constituent particles, short distances and strong interactions between them. In amorphous solids, the arrangement of constituent particles has only short range order and consequently they behave like super cooled liquids, do not have sharp melting points and are isotropic in nature. In crystalline solids there is long range order in the arrangement of their constituent particles. They have sharp melting points, are anisotropic in nature and their particles have characteristic shapes. Properties of crystalline solids depend upon the nature of interactions between their constituent particles. On this basis, they can be divided into four categories, namely: molecular, ionic, metallic and covalent solids. They differ widely in their properties.
The constituent particles in crystalline solids are arranged in a regular pattern which extends throughout the crystal. This arrangement is often depicted in the form of a three dimensional array of points which is called crystal lattice. Each lattice point gives the location of one particle in space. In all, fourteen different types of lattices are possible which are called Bravais lattices. Each lattice can be generated by repeating its small characteristic portion called unit cell. A unit cell is characterised by its edge lengths and three angles between these edges. Unit cells can be either primitive which have particles only at their corner positions or centred. The centred unit cells have additional particles at their body centre (bodycentred), at the centre of each face (face-centred) or at the centre of two opposite faces (end-centred). There are seven types of primitive unit cells. Taking centred unit cells also into account, there are fourteen types of unit cells in all, which result in fourteen Bravais lattices.
Close-packing of particles result in two highly efficient lattices, hexagonal close-packed (hcp) and cubic close-packed (ccp). The latter is also called facecentred cubic (fcc) lattice. In both of these packings 74% space is filled. The remaining space is present in the form of two types of voids-octahedral voids and tetrahedral voids. Other types of packing are not close-packings and have less efficient packing of particles. While in body-centred cubic lattice (bcc) 68% space is filled, in simple cubic lattice only 52.4 % space is filled.

Solids are not perfect in structure. There are different types of imperfections or defects in them. Point defects and line defects are common types of defects. Point defects are of three types - stoichiometric defects, impurity defects and non-stoichiometric defects. Vacancy defects and interstitial defects are the two basic types of stoichiometric point defects. In ionic solids, these defects are present as Frenkel and Schottky defects. Impurity defects are caused by the presence of an impurity in the crystal. In ionic solids, when the ionic impurity has a different valence than the main compound, some vacancies are created. Nonstoichiometric defects are of metal excess type and metal deficient type. Sometimes
calculated amounts of impurities are introduced by doping in semiconductors that change their electrical properties. Such materials are widely used in electronics industry. Solids show many types of magnetic properties like paramagnetism, diamagnetism, ferromagnetism, antiferromagnetism and ferrimagnetism. These properties are used in audio, video and other recording devices. All these properties can be correlated with their electronic configurations or structures.

Friday, February 22, 2013

Born on 5 July 1904, in Kempten, Germany, ERNST MAYR, the Harvard University evolutionary biologist who has been called ‘The Darwin of the 20th century’, was one of the 100 greatest scientists of all time. Mayr joined Harvard’s Faculty of Arts and Sciences in 1953 and retired in 1975, assuming the title Alexander Agassiz Professor of Zoology Emeritus. Throughout his nearly 80-year career, his research spanned ornithology, taxonomy, zoogeography, evolution, systematics, and the history and philosophy of biology. He almost single-handedly made the origin of species diversity the central question of evolutionary biology that it is today. He also pioneered the currently accepted definition of a biological species. Mayr was awarded the three prizes widely regarded as the triple crown of biology: the Balzan Prize in 1983, the International Prize for Biology in 1994, and the Crafoord Prize in 1999. Mayr died at the age of 100 in the year 2004.

Thursday, February 21, 2013

The change in frequency caused by a moving object due to Doppler effect is used to measure their velocities in diverse areas such as military, medical science, astrophysics, etc. It is also used by police to check over-speeding of vehicles. A sound wave or electromagnetic wave of known frequency is sent towards a moving object. Some part of the wave is reflected from the object and its frequency is detected by the monitoring station. This change in frequency is called Doppler shift.
It is used at airports to guide aircraft, and in the military to detect enemy aircraft. Astrophysicists use it to measure the velocities of stars.
Doctors use it to study heart beats and blood flow in different part of the body. Here they use ulltrasonic waves, and in common practice, it is called sonography. Ultrasonic waves enter the body of the person, some of them are reflected back, and give information about motion of blood and pulsation of heart valves, as well as pulsation of the heart of the foetus. In the case of heart, the picture generated is called echocardiogram.

Temples often have some pillars portraying human figures playing musical instruments, but seldom do these pillars themselves produce music. At the Nellaiappar temple in Tamil Nadu, gentle taps on a cluster of pillars carved out of a single piece of rock produce the basic notes of Indian classical music, viz. Sa, Re, Ga, Ma, Pa, Dha, Ni, Sa. Vibrations of these pillars depend on elasticity of the stone used, its density and shape.
Musical pillars are categorised into three types: The first is called the Shruti Pillar, as it can produce the basic notes — the “swaras”. The second type is the Gana Thoongal, which generates the basic tunes that make up the “ragas”. The third variety is the Laya Thoongal pillars that produce “taal” (beats) when tapped. The pillars at the Nellaiappar temple are a combination of the Shruti and Laya types.
Archaeologists date the Nelliappar temple to the 7th century and claim it was built by successive rulers of the Pandyan dynasty.
The musical pillars of Nelliappar and several other temples in southern India like those at Hampi (picture), Kanyakumari, and Thiruvananthapuram are unique to the country and have no parallel in any other part of the world.

born in Vienna, Austria, worked on the kinetic theory of gases independently of Maxwell. A firm advocate of atomism, that is basic to kinetic theory, Boltzmann provided a statistical interpretation of the Second Law of thermodynamics and the concept of entropy. He is regarded as one of the founders of classical statistical mechanics. The proportionality constant connecting energy and temperature in kinetic theory is known as Boltzmann’s constant in his honour.

Wednesday, February 20, 2013

He made a brilliant guess that equal volumes of gases have equal number of molecules at the same temperature and pressure. This helped in understanding the combination of different gases in a very simple way. It is now called Avogadro’s hypothesis (or law). He also suggested that the smallest constituent of gases like hydrogen, oxygen and nitrogen are not atoms but diatomic molecules.

Though John Dalton is credited with the introduction of atomic viewpoint in modern science, scholars in ancient India and Greece conjectured long before the existence of atoms and molecules. In the Vaiseshika school of thought in India founded by Kanada (Sixth century B.C.) the atomic picture was developed in considerable detail. Atoms were thought to be eternal, indivisible, infinitesimal and ultimate parts of matter. It was argued that if matter could be subdivided without an end, there would be no difference between a mustard seed and the Meru mountain. The four kinds of atoms (Paramanu — Sanskrit word for the smallest particle) postulated were Bhoomi (Earth), Ap (water), Tejas (fire) and Vayu (air) that have characteristic mass and other attributes, were propounded. Akasa (space) was thought to have no atomic structure and was continuous and inert. Atoms combine to form different molecules (e.g. two atoms combine to form a diatomic molecule dvyanuka, three atoms form a tryanuka or a triatomic molecule), their properties depending upon the nature and ratio of the constituent atoms. The size of the atoms was also estimated, by conjecture or by methods that are not known to us. The estimates vary. In Lalitavistara, a famous biography of the Buddha written mainly in the second century B.C., the estimate is close to the modern estimate of atomic size, of the order of 10 –10 m.
In ancient Greece, Democritus (Fourth century B.C.) is best known for his atomic hypothesis. The word ‘atom’ means ‘indivisible’ in Greek. According to him, atoms differ from each other physically, in shape, size and other properties and this resulted in the different properties of the substances formed
by their combination. The atoms of water were smooth and round and unable to ‘hook’ on to each
other, which is why liquid /water flows easily. The atoms of earth were rough and jagged, so they held
together to form hard substances. The atoms of fire were thorny which is why it caused painful burns.
These fascinating ideas, despite their ingenuity, could not evolve much further, perhaps because they
were intuitive conjectures and speculations not tested and modified by quantitative experiments - the
hallmark of modern science.

Lord Kelvin (William Thomson) (1824-1907), born in Belfast, Ireland, is among the foremost British scientists of the nineteenth century. Thomson played a key role in the development of the law of conservation of energy suggested by the work of James Joule (1818-1889), Julius Mayer (1814- 1878) and Hermann Helmholtz (1821-1894). He collaborated with Joule on the so-called Joule-Thomson effect : cooling of a gas when it expands into vacuum. He introduced the notion of the absolute zero of temperature and proposed the absolute temperature scale, now called the Kelvin scale in his honour. From the work of Sadi Carnot (1796-1832), Thomson arrived at a form of the Second Law of Thermodynamics. Thomson was a versatile physicist, with notable contributions to electromagnetic theory and hydrodynamics.

Rudolf Clausius (1822-1888), born in Poland, is generally regarded as the discoverer of the Second Law of Thermodynamics. Based on the work of Carnot and Thomson, Clausius arrived at the important notion of entropy that led him to a fundamental version of the Second Law of Thermodynamics that states that the entropy of an isolated system can never decrease. Clausius also worked on the kinetic theory of gases and obtained the first reliable estimates of molecular size, speed, mean free path, etc.

Daniel Bernoulli was a Swiss scientist and mathematician who along with Leonard Euler had the distinction of winning the French Academy prize for mathematics ten times. He also studied medicine and served as a professor of anatomy and botany for a while at Basle, Switzerland. His most well known work was in hydrodynamics, a subject he developed from a single principle: the conservation of energy. His work included calculus, probability, the theory of vibrating strings, and applied mathematics. He has been called the founder of mathematical physics.

Archimedes was a Greek philosopher, mathematician, scientist and engineer. He invented the catapult and devised a system of pulleys and levers to handle heavy loads. The king of his native city Syracuse, Hiero II asked him to determine if his gold crown was alloyed with some cheaper metal such as silver without damaging the crown. The partial loss of weight he experienced while lying in his bathtub suggested a solution to him. According to legend, he ran naked through the streets of Syracuse exclaiming “Eureka, eureka!”, which means “I have found it, I have found it!”